Heat exchange apparatus



Aug. 29, 1939. I H, c, c ns'o ET AL 2,171,047

HEAT EXCHANGE APPARATUS 3 Sheets-Sheet 2 Filed Feb. 24; 1937 INVENTORS IHOLDEN C P/c/m/eaao/v.

fle/vev AAMPE 2 BY I ATT RNEYS- 29, 1939- H. c. RICHARDSON ET AL,171,047

HEAT EXCHANGE APPARATUS Filed Feb. 24, 195'? s Sheets-Sheet s W 9 m EmmQR m O. CE A Patented Aug. 29, 1939 UNITED STATES, PATENT OFFICE Holden0. Richardson, Washington, D. 0., and Henry Kampl', New York, N. Y.

' Application February 24, 1937, Serial N0. 127,356

13 Claims. (emu-57) This invention relates to heat exchange apparatusand particularly to heat exchange apparatus designed for use with thepower plants of airplanes'for cooling or condensing purposes.

In the air-cooled motors used with airplanes at the present time,advantage is taken of the slip stream from the propeller for supplyingair for cooling purposes and one of the objects of the present inventionis so to construct and to arrange cooling means, such as radiators, orcondensers for a steam-driven power plant for airplanes, that they canmake best use of the air coming from the slip stream to efiect incomparatively close quarters a comparatively large heat exchange, with aminimum disturbance of flow of air over the adjacent wing surfaces.

As herein illustrated, the invention is shown as embodied in'a condenserfor condensing the steam from a'steam turbine or a steam engine utilizedto drive thepropeller of the airplane and an important object of theinvention is so to construct the condenser that substantially uniformcondensing results can be obtained throughout the condensingstructureeven though because of space limitations the cooling air mustpass .over some of theparts of the condenser after it has already passedover others, and eventhough the tube lengths vary inproportion to theradial distance of their axes-from the axis of the condenser.

-An important feature of the invention is the symmetrical arrangement ofthe elements of the condenser with respect to the propeller axis whichcontributes markedly to the'efiective operation of the difierent partsof the condenser. Another important feature of the invention is thecon-,

trol of the distribution of the steam to be condensed to the differentparts of the condenser whereby "the steam is apportioned to the variousparts in proportion to their condensing or heatexchanging capacity.

Another important feature'of the invention is the utilization ofdirecting means, preferably stream-lined and so constructed and arrangedas to convert the velocity of the slip stream into .pressure whereby, asthe airenters the conduit to the condenser, its expansion-beyond theentrance tends to convert velocity to pressure at the face of thecondenser, and then by the use of Venturi-shaped passages reconvertpressure to increased velocityand to direct the air stream into the airpassages in the condenser without undue eddy losses at the entranceto'same.

Notmnly does the invention aim to improve,

the means which, control the supply of cooling air to the condenser, butthe invention aims also to provide improved arrangements fordischarging. the air after it. has taken up the heat from the condenser.Important features of the improved discharge arrangement are theprovision 5 of means for insuring a smooth discharge and the breakingupof eddies'and whirls before the air is discharged into the streampassing over the plane wing and also an arrangement whereby thedischarge comes at such a point on the wing 0 that it tends to removethe'boundary layer of air and thereby augment the wing lift, while alsoaugmenting the differential pressure between the entrance and exit.

Figure 1 is-a section through theforward part of the wing of an airplaneand through the motor or turbine cowling, illustrating a condenserembodying the present invention, with passages 10- cated at the rear,and at both sides'of the propeller shaft;

Figure 2v is a sectional .plan view of Figure 1; I Figure 3 is a sectionon the line 3-3 of Figure 1;

Figure 4 is a section on the line 4-4 of Figure 1;

Figure 5 is a plan, partly in section; of a con- J denser embodying thepresent invention;

. Figure 6 is a vertical section illustrating a condenser arrangedconcentrically about the propeller shaft and located near the front '01the I cowlingpwith the discharge for the air that has traversed thecondenser located near the front of the cowling;'

Figure 7 is a vertical section showing a similar arrangement of thecondenser but arranged to discharge the cooling air on the under side ofthe wing;

Figure 8 is a section through the condenser Of Figure 7;

Figure 9.is a detail section of the input end of 40 one of the condensertubes,. and

Figure 10 illustrates the nozzles for controlling the input oi! steaminto the condenser tubes.

Figure 11 illustrates a method of controlling the input of steam to thecondenser tubes by restricting the diameter of the tube.

In the embodiment of the invention illustrated particularly'in Figures1, 2, 6 and 7 inclusive, the motor 2, for driving the propeller 4 byconnections thereto, including'the propeller shaft 6, may be of anysuitable type, such, for example, as a steam turbine ina steam poweredairplane, the exhaust .steam fromthe turbine 2 going through a conduit8, Figuresl and '7, to a manifold IOat the top of the condenser I2.

That part of. the propeller connections and turbine 2 which extendsbeyondthe forward edge of the airplane wing it is enclosed in a cowlingI6, stream-lined to direct the slip stream from the propeller over andunder the wingv surfaces. The cowling It, at its forward end, projectsslightly over a spinner It, surrounding and connected to the hub of thepropeller 4 and provided with a stream-lined nose 20, this arrangementproviding an intake passage 22 for the cooling air for the condenser l2.The cooling air, being a part of the slip stream, e ters the passage 22at a velocity considerably in excess of the velocity of movement of thewing I through the 'air.

In the embodiment'of the invention shown in Figs. 1 to 4 inclusive, theair intake passage 22 is at the forward end of an airconduit 24 passingsymmetrically past the turbine 2 to conduct the air from the intake 22to the condensers 12. This conduit 24 is continued beyond the condensersI2 to the upper surface of the wing l4 where it discharges the air afterit has picked up the heat from the condenser I2, this discharge beingeffected in such away as to tend to remove the boundary layer of airclinging to the upper surface of the wing and thus aid the forces whichlift the plane, by delayingburbling. At its discharge end each conduit24 is preferably provided with stream-lined guides 26 which serve tosmooth out eddies that may have formed in the air stream in its passagethrough the conduits 2'4 and thus insure its discharge on the uppersurface of the wing in a smooth flowing stream merging into the airstream-passing over the to heat exchange.

upper surface of the wing with augmented veloc-* ity in a region ofreduced pressure.

In the form of the invention shown in Figs. 1 to 5 inclusive, thecondenser is made up of upright condenser 'tubes 28 which extend fromthesteam manifold It to the water manifold 30, these tubes beingpreferably provided with fins 32 such as shown in Fig. 9 to increase therate of heat exchange. At the intake end of the condenser l2stream-lined guides '34 are'provided which serve two purposes: First,they are so 10- cated with respect to the first row of condenser tubes28 that they guide the cooling air against the median lines of thesetubes and, secondly, by their shape and relation to each other theyproduce a Venturi effect whereby pressure is conis desired 'to admit toa particular tube, Fig. 10

. showing a slightly different form of the nozzle passage from thatshown in Fig. 9.

In the form of the invention shown in Figures 1 to 5 inclusive, theconduit 24, as hereinabove suggested, carries the air past the turbine 2to direct it into the condensers l2, although the scoop-like intakepassage 22 is concentric with the turbine driven shaft and extends aboutthe axis of said shaft. The entrance 22 being of somewhat smaller crosssectional area than that part of the conduit 24 behind the entrance, theI air is driven into the entrance 22 by the slip stream and thus, as itexpands behind the enincreasing pressure to the face of the condenser,where velocity is regained as the air passes through the Venturipassages, to the cooling elements.

In the forms of the invention shown in Figures 6, '7 and 8, thecondenser I2 is arranged concentrically about the axis of the propellershaft 6 v, and is of the construction described in more deverted toincreased velocity corresponding to that in the passages through thecondenser, the air passing in sinuous streams over the staggered rows ofcondenser tubes in'such manner that it passes from the tips of the finsof one stage of tubes to the base of the fins of the next, and viceversa, thus establishing a turbulence beneficial It will be obvious thatthe anentering the forward. end of the condenser will have pickedupconsiderable heat from the first rows of tubes of the condenser beforeit reaches the rearend of the condenser and that, therefore, itscapacity for absorbing heat from these rear tubes will be tailhereinafter.

y In the form of the invention shown in Figure 6, the air from thepropeller slip stream enters an annular entrance 22 into a conduit 40which is formed between a sheet metal guide wall 42, constitutingal so apartition between the conduit 40 and anannular exhaust air passage 44surrounding the conduit 40, and an inner guide wall 46 .surrounding thepropeller shaft 6. The conduit 40 is of such shape that the air, afterit has gone through the entrance passage 22, is allowed to expand beforeit enters the condenser I2. The outer wall, of the discharge passage 44is formed by the cowling It.

The wall 46 of the conduit 40 is extended through the condenser l2 andis then 'curvedup to .meet the cowling l6 and thuscomplete the conduit44, as shown in Figure 6. .The'discharge passage 44 is completed by atorus-like member 48 having its inner edge connected to the wall 42 andhavingits outer edge connected to the shield 50 in such manner that thefront edge of the cowling "5 forms a streamline nose for the torus. Theair from the discharge passage 44 is thus discharged directly into theslip stream, in aregion of reduced pressure augmenting the flow. InFigure 7 the conduit 40 for the cooling air is formed directly betweenthe inner wall 46' and the cowling l6 and the conduit is completedbeyond the condenser [2' by a guide wall 52 which directs the stream ofair, after it has passed through the condenser l2, to a discharge 54 inthe lower part of the cowling, so that the air, after it has picked upthe heat from the condenser [2, passes through vanes 26 and enters thestream of air flowing over the under side ofthewingl4. v

'Ihe condenser. l2, asshown particularly in Figures '1 and 8, comprisesa series of substantially'semi circula'r condenser tubes 28' whichexconsiderably reduced. Tojcompensate'for'this,

so as to insure proportionate condensing action in each of the tubes,theinput ofsteam into each of the tubes 28 is preferably metered, at.least in those tubes ,in the rows behind the initial row. This meteringmay be effected byinsert-f ing into the ends of the respective tubesopening into the steam manifold Ill, nozzles 36, or any other'well knownmeans of restriction, the restricted orifices 38- of which may vary indiametc; in accordance with the amount of steam it water header .52, ofsimilar construction, on the tendbetween a steam header iflsector-shapedin cross-section, anda water header 58, likewise sector-shaped incross-section, on the one side or the condenser and between a steamheader 60,. also sector-shaped incross-section, and a other. side .ofthe condenser. Supporting and spacing diaphragms maintain the tubes 28'in proper, relation to each' other, these 'diaphragms extending betweenthe inner air. guiding wall 56 of the condenser and the outer airguiding wall 7 68, both of these walls being preferably corrugated as.shown in Figure 7 to assist in efiecting a sinuous flow of the air overthe tubes of the condenser adjacent to the outer and inner walls 5thereof.

' The steam to be'condensed enters thesteam headers 56 and 60 throughpipes I and the condensed steam or water leaves the water headers 58 and62 through 'pipes'IZ. r

The condenser l2 preferably *has stream-lined guides 34 ofthe samecharacter as'those provided for'the condenser I 2, except that theirlongitudinal contours correspond with the longitudinal contours of thecondenser pipes28. I

From the foregoing description, it will be ob.- vious that a compact andeflicient condenser or cooling construction has beenv provided whichtakes into consideration the space .and weight limitations in airplaneconstruction and, at the 20 'same time, utilizes existing air flowstoproduce, with as little disturbance of sustaining forces as possibleand with as little loss of propulsive power as possible, a maximum ofheat exchanging efiect. What is claimed as new is: g I 25 1. Condensingmeans for use in condensing steam in steam-driven aircraft having apropeller and a driving shaft therefor, saidcondensingmeans comprising,in combination, banks of.

steam condensing tubes extending concentrically to about the axis of thepropeller shaft and a conduit forcondenser cooling air of annular crosssection to and through said condensing means having an annular intakebehind said propeller to receive va portion of the slip stream therefromand, having a discharge so located as to discharge the air into a lowpressure area, sad banks of con-' densingtubes forming an annularstructure filling a cross sectional zone of said conduit ofsubstantially greater cross section than the intake ,0 part of saidconduit.

2.- Condensing means for use in condensing steam in steam-drivenaircraft having a propeller.

and a driving shaft therefor, said condensing means comprising, incombination, banks of steam ,5 condensing tubes extending concentricallyabout the axis .of the propeller shaft and a conduit for condensercooling air having an annular intake behind said propeller to receive aportion of the slip stream therefrom and having a discharge so 0 locatedas to dischargethe air into a low pressure area, said'condensing tubesforming an annular structure filling a cross sectional zone of saidconduit and said conduit being of annular cross section to and throughsaid condenser and increas- 5 ing progressively in cross-sectional areafrom said annular intake to said condenser.

- Condensing means for use in condensing r steam in steam-drivenaircraft having a propeller and a driving shaft therefor, said con- [idensing means comprising, in combination, banks a of steam condensingtubes extending concentrically about the axis of the propeller-shaft anda conduit for condenser cooling air of annular cross section to andthrough said condenser and hav- 5 ing an intake behind said propeller toreceive a ,portion of the slip stream therefrom and having a dischargesolocated as to discharge the air into a low pressure area; saidcondensing tubes forming an annular structure filling a cross sectionalzone yof said conduit of substantially greater cross sec- Condensingmeans for use in condensing steam in steam-driven aircraft havingapropeller and-a driving shaft therefor, said condensing meanscomprising, -in combination, banks of steam condensing tubes extendingconcentrically 5 about the axis of the propeller shaft and a conduitfor' condenser cooling air of annular cross section to and through-saidcondenser having an intake behind said propellerto receive a portion ofthe slip stream therefrom andhaving a dis- 1 charge so located as'todischarge the air into a low pressure area, said banks of-condensingtubes forming an annular structure filling across sectional zone of saidconduit of substantially greater cross section than the intake part ofsaid conduit and comprising two groups each made up of a steam headerand a substantially diametrically opposed water header, banks ofsubstantially semi-circular tubes connecting said headers, the

vtubes of sucessive banks in the direction of air movementbeing'staggered, and correspondingly curved stream-lined vanessoarranged as to dimet the air' against the respective condensing tubes ofthe first bank and at the same time reduce eddy'losses.

5. In an airplane having a steam driven propeller, a steam poweredmotor, and -a bowling enclosing .said motor, means for condensing thesteam from said motor'comprising, in combination, a conduit for coolingair for said condenser extending through said cowling from an intakebehind the propeller to a discharge adjacent to one of the wingsurfaces, and-a condenser in said conduit comprising a steam header, awater header and successive banks of tubes connecting said headers,means for insuring uniform distribution of the cooling air over thetubes of the various banks and means at the intake ends of the tubes vofcertain"banks adapted to apportion the input of steam intosaid tubes tothe heat-absorbing capacity of the air when it reaches said banks.-

6. Heat exchange apparatus for airplanes comprising, in combination withthe motor, the motor cowling and propeller, guides cooperating with saidcowling to form an annular air passage with a restrictedannular openingarranged to receive a part of the propeller slip stream, banks of heatexchanging tubes arranged in said passage with the tubes of each bank instaggered relation to those of adjacent banks in the direction ofmovement of air through the passagaand means for concentrating the airupon the tubes of the first bank, said means being stream-lined toeliminate eddies.

7; Heat exchange apparatus for'airplanes comprising, in combination withthe motor, the motor cowling and propeller, guides cooperating with saidcowling to form an annular airpassage with a restricted annular openingarranged to receive a part of the propeller slip stream, banks of heatexchanging tubes arranged in said passage with the tubes of each bank instaggered/relationto those of adjacent banks in the direction ofmovement of air through the passage, means for concentrating the airuponthe tubes of the first bank, said means being stream-lined to eliminateeddies, and means comprising sinuously curved surfaces for insuringanundulatory movement of I the air through said' heat exchanger.

8. In an airplane, in combination with a wing thereof, a propellermounted on the wing, a motor for'driving the propeller, a cowlingenclosing said motor, and heat exchanging elements located withi'r saidcowling, of means concentri- 4 cally arranged about the propeller shaftto provide a continuous air passage from an annular scoop entrancearranged to receive a portion of the slip stream from the propeller intoan expan'ding annular passage extending through the condenser and thencethrough a contracting, velocity accelerating passage to air exhaustapertures to the rear of the cowling, said heat exchange elements beinglocated within and intermediate between the ends of saidpassage, andstream-lined vanes defining said exhausttapertures and serving toeliminate eddies in the stream of heated air discharged therethrough.

9. An air cooled heat exchanger concentrically and symmetrically,arranged about an axisand comprising, in combination, sector shapedintake manifolds, sector shaped exhaust manifolds, and

tubular heat exchange members concentrically curved about said axis toform successive banks of tubes connecting said manifolds and affordingmultiple passages for the fluid to be cooled between the intake andexhaust manifolds, and means comprising entrance defining stream-linedvanes and a sinuously curved surrounding cas ing for directing the airthrough said banks of tubes in a direction substantially parallel to theaxis about which they are curved.

10. An air cooled heat exchanger concentrically and symmetricallyarranged about an axis and comprising, in combination, sector shapedintake manifolds, sector shaped exhaust manifolds, and tubular heatexchange members concentrically curved about said axis to form'successive banks of tubes connecting said. manifolds and affordingmultiple passages for the fluid to. be cooled between the intake andexhaust manifolds, means for directing the air through said banks oftubes in a direction substantially parallel tothe axis about which theyare curved, said means comprising a sinuously curved surrounding casing,and stream-lined guide members also concentrically and symmetricallyarranged about said axis and so located as toconcentrate the cooling airin eddyfree streams upon the axes of the curved tubular cooling membersof the first bank.

' 11. In an airplane, the combination with a propeller and propellershaft, the airplane win and propeller supporting means intermediatebetween the propeller and front spar of said wing, of cooperatinginterior and exterior guiding elementc, coaxially and concentricallymounted aboutthe propeller shaft to form a continuous air passage froman annular scoop in the propellerrslip'stream into a symmetricalexpanding and contracting passage ending in air exhaust apertures, saidapertures being formed as a series of contracting passages in the uppersurface of the wing to the rear of the front spar in a region of lowpressure, and long deep-curved air foil elements in said passagesarranged to obtain a boundary layer removal effect and to discharge theair at high speed smoothly into the passing air stream. V

12. Condensing means for use in condensing steam in steam-drivenaircraft having a propeller and a driving shaft therefor, saidcondensing means comprising, in combination, banks of steam condensingtubes extending concentrically about the axis of the propeller shaft anda conduit for condenser cooling air of annular cross section to andthrough said condenser having an annular intake behind said propeller toreceive a portion of the slip stream therefrom and having a discharge solocated as to discharge the air into a low pressure area, said banks ofcondensing tubes being located in said conduit and comprising two groupseach made up of -a steam header and a substantially diametricallyopposed water header, and substantially semi-circular tubes connectingsaid headers, means for insuring uniform distribution of the cooling airover the respective tubes of said condenser, and means at the intakeends of the tubes of certain banks adapted to apportionthe input ofsteam into said tubes to the length thereof as determined by theirradial distances from the axis of the condenser.

13. Condensing means for use in condensin steam in steam-driven aircrafthaving a propeller and a driving shaft therefor, said condensing meanscomprising, in combination, banks of steam condensing tubes extendingconcentrically about the axis of the propeller shaft and a conduit ofannular cross section for the condenser cooling air, said conduit havingan annular intake behind said propeller to receive a, portion of theslip stream therefrom and having a' discharge so located as to dischargethe air into a low pres-' sure area, said condensing tubes forming anannular structure filling a cross-sectional zone of said conduit andsaid conduit being of annular cross section to and through saidcondenser and to said discharge, the portion of said conduit on thedischarge side of said condenser comprising an outer reversel'ydirectedportion surroundin the partextending through said condenser andincluding a torus-like end portion directing the discharged air into thedirection of flow of the propeller slip stream. v

' HOLDEN C. RICHARDSON.

HENRY KAMPF.

